Step 1In a large bowl, stir together the ricotta, Parmigiano, parsley, salt and egg until the mixture is smooth and well-combined. Add three-fourths cup flour and continue stirring until it is fully incorporated. Continue to stir in the flour, a tablespoon or 2 at a time, until the mixture forms a soft dough that holds together but may feel slightly damp; this should take a total of about 1 cup of flour. Remove the dough from the bowl and knead it on a lightly floured board until the dough is smooth, pliable and a little sticky.
Step 2To shape the gnocchi, divide the dough into quarters. Flour your hands lightly (do not flour the work surface). Working with 1 piece at a time, use both hands to roll out the piece of dough with a light back-and-forth motion into a rope about one-half- to three-fourths-inch thick. Cut the roll into 1-inch pieces. Line a jellyroll pan with a lightly floured tea towel and transfer the gnocchi to it. Sprinkle lightly with flour and refrigerate for at least 10 minutes.
Step 3Hold a fork with its tines against the work surface, the curved part of the fork facing away from you. Starting from the bottom of the tines of the fork, press each piece of dough with your index finger firmly upward along the length of the tines, then let the gnocchi fall back onto the work surface. Repeat with the remaining dough until all the gnocchi have been formed. Return the gnocchi to the jellyroll pan and set aside until ready to use.
Step 1Clean the artichokes: Fill a large bowl with cool water and add the lemon juice. Trim away each artichoke's tough outer leaves, then cut off the top half-inch of the tip and peel the base and stem. Quarter the baby artichokes and cut the larger artichokes lengthwise into 8 pieces. Keep the artichokes submerged in the lemon water to prevent browning and set aside.
Step 2Place the shelled fava beans in a large bowl and pour boiling water over to cover. Let stand until the water is cool enough to touch. Use your thumbnail to cut a slit in the thin membrane surrounding each fava and squeeze the bright green bean halves into a bowl. Discard the membranes. Repeat with all the favas and set aside.
Step 3Cut the tough bases and tender tips from the asparagus and reserve the tips (discard the bases). Peel the asparagus and cut crosswise into 1-inch sections.
Step 4Trim the roots and most of the green stems of the bulbing onions and halve them lengthwise.
Step 5Melt 2 tablespoons butter in a large skillet over medium heat and add the shallots. Cook until the shallots soften, about 3 minutes. Add the artichokes, the white wine and water, cover tightly and cook until the artichokes are just tender enough to pierce with a paring knife, 5 to 15 minutes (the time will vary depending on the freshness and type of the artichoke).
Step 6Add the chopped asparagus stalks, replace the cover and cook until they are tender, about 3 minutes. Stir in the bulbing onions, the asparagus tips and the tarragon and cook until the tips are bright green and tender, about 3 minutes. Season to taste with salt and reduce the heat to low to keep warm.
Step 7Bring a wide pot of water to a rolling boil and salt generously. Reduce the heat to a slow boil and add the gnocchi to the pot (reducing the heat helps keep the gnocchi from breaking up). Stir gently to lift them from the bottom of the pot and cook until they float to the surface, 1 to 2 minutes, then cook them an additional 20 to 30 seconds and retrieve them with a strainer, transferring them directly to the vegetable stew.
Step 8Increase the heat under the stew to high and add the remaining 2 tablespoons of butter. Stir gently to coat the gnocchi with the glaze and divide among 6 heated pasta bowls. Sprinkle grated Parmigiano over the top and pass more at the table. Serve immediately.